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You have a collection that

contains zip codes in the United States.

Here’s a sample

document from this collection:

What will the output of

this aggregation pipeline be?

One

document for each state in United States except Texas (TX)

All

documents that contain a city where the state is Texas (TX)

One document for each city located in Texas

(TX)

One

document containing all cities located in Texas (TX)

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What happens when you create a TTL (Time-To-Live) index on a field in MongoDB?

The index enforces a time-based ordering of documents.

The field values are encrypted.

The index ensures that field values automatically expire after a certain duration.

Documents with expired field values are automatically removed from the collection.

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What is the main difference between $set and $project?

$project,

$set, and $addFields are all interchangable.

$set is used to create or change values of new

or existing fields. $project can be used to create or change the value of

fields, but it can also be used to specify which fields to show in the

documents in the aggregation pipeline.

✅

$set

changes the values of fields. $project can show and hide fields, but it can't

set values of fields.

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Choose correct queries with different

count methods available in MongoDB aggregation framework?

db.persons.aggregate([]).size();

db.persons.aggregate([{

$group: { _id: "$customer.gender" } },{ $count: "genderCount"}]);

db.persons.aggregate([{$count:"total"}]);

db.persons.aggregate([]).itcount();

db.persons.aggregate([]).length([1]);

db.persons.aggregate([]).toArray().length;

db.persons.aggregate([

{ $group: { _id: "$customer.gender", count: { $sum: 1 } } }]);

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What does return TRUE if the cursor returned by the db.collection.find() query can iterate further to return more documents? (Select one)

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What method does return an array that contains all the documents from a cursor? (Select one)

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How can you delete all documents from a collection in MongoDB?

Using the db.collection.deleteMany({}) method.

✅

Using the db.collection.remove({}) method.

Using the db.collection.removeAll() method.

Using the db.collection.deleteAll() method.

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The _______ operator can be used to identify an element in the array to be updated without explicitly specifying the position of the element.:

Updating an array field without knowing its index is not possible

$slice

$elemMatch

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You have a collection

that contains zip codes in the United States.

Here’s a sample
document from this collection:

What will the output of

this aggregation pipeline be?

One

document for the population of each zip code, sorted in ascending order

One

document for the population of each zip code, sorted in random order

One

document for the population of each zip code, sorted in descending order

documents for the population of each zip code

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How to get next document in the cursor returned by the db.collection.find() method. (Select one)

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